Analysis of Economic Losses From Phase Imbalance in a Wastewater Treatment Facility

Phase imbalance is a phenomenon in which the three phases of an electrical system differ by more than 10% in magnitude and/or phase. Most electrical systems are capable of operating through this imbalance for long periods of time without noticeable failures. However, prolonged imbalance will cause sustained wear to the motor windings and increases in electric utility charges. This paper presents a method for calculating the economic loss within the electric utility charges to provide justifications for electrical infrastructure projects. The paper utilizes effective power and positive sequence components to calculate the percent phase imbalance. An example project using real data from a wastewater treatment facility is provided to demonstrate the appropriate application of the calculations. The key findings are a reduction in electric utility charges by up to 20% through phase balancing systems.